docs: def _proxy_parameters(self):
          """
          Builds Proxy parameters Dict from
          client options.
          """
  
          proxy_protocol = ''
          if self.proxy_host.startswith('https'):
              proxy_protocol = 'https'
          else:
              proxy_protocol = 'http'
  
          proxy = '{0}://'.format(proxy_protocol)
          if self.proxy_username and self.proxy_password:
              proxy += '{0}:{1}@'.format(self.proxy_username, self.proxy_password)
  
          proxy += sub(r'https?(://)?', '', self.proxy_host)
  
          if self.proxy_port:
              proxy += ':{0}'.format(self.proxy_port)
  
          return {
              'http': proxy,
              'https': proxy
          }